Improvement in engines for the use of steam and air combined



1. B. 'TARR.

Engifi for th Use of Air and Steam Combined-,1 Q PatentdfNov. 26. 1867.!

, UNITED STATES" IMPROVEMENT IN ENGINES FOR THE USE OF STEAM AND AlR COMBlNEDh' Specification forming part of Letters Patent No. 7|, l25, dated November 26,. 1867 5 1 To all whom it may concern:

Be it known that 1, JOHN BLAKE TARR, of Chicago, in the county of Cook, and State of Illinois, have invented an Improvement in Steam-Engines; and I do hereby declarethe following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this specification, in which- Figure 1 is a perspective view, showing my invention applied to a horizontal or stationary engine- Figure 2 is a side elevation of the same with boiler attached.

gether in the steam-chest on their way to the cylinder of the engine, thus efiecting a re-' heating or superheating of the steam after it leaves the boiler and while it is confined within the steam-chest and cylinder.

To enable others skilled in the art to understand my invention,'I will describe one mode p of carrying it into efiect.

In the accompanying drawings I have represented my invention applied to a stationary high-pressure engine, but I do not desire tov be understood as confining it to this form of as it is applicable to other forms of steam-engines. A represents this steam-cylinder mounted upon a bed, B, and provided with a valve-chest, C, slide-valve, exhaustingengine,

, ports, like anywell-known form of stationary engine. D D represent steam-pipes, which connect at their lower ends with a single pipe, D leading into the valve-chest O, for the purpose of conducting highly-heated air and common steam within the steam chest, from whence they are allowed toescape into the "cylinder, by the reciprocatingmovements of the slide-valve, and to act alternately upon both ends of the piston in a mannercommon to high-pressure steanrengines' generally. 'The pipes D D are both provided with oscillating I or other suitable forms of valves, the stems a a, of whichhave arms, I) 11'', secured to them,

- by which they are moved or oscillated. The r arms I) b are connected to the arms of an os- JonN BLAKE TARR, or oincAco, ittinois.

' cillating lever, G, arranged below the pipesfl to said pipes g g by means of PATENT OFFICE.

D D, which lever receives its1motions fromi an arm, 0, on the rock-shaftlc, which moves; the slide-valve. The arm c: and roclshaft c receive motion from the main fl vheelshaft i L, through the mediuinof an ntric,P, and pitman-rod, R, as shown in a 1 e;d1iawings Thus it will be seen that as far as, the engine. is concerned, there is very little} changersquired to apply my invention torit. The only change really required is the two :pipes D D for bringing the steam and air from suitable reservoirs in separate channels, so that th air and steam shall not be. mixed until theyi enter the valve-chest G,said pipes both being; a provided with valves for letting i on i and: cut ting off the steam and air,and alternately and l at proper times. The steam+pipeiD leads off a to a steam-boiler, fwhich may be made as shown in Fig. 2, or of any other suitable form, and the air-pipe D leads off. to, a series of; pipes, g g, which may be arranged within the fire-space of said boiler, as shown, or which may be otherwise suitably arranged. I prefe to have the air-heating pipes within the fire place or furnace of the boiler 0 71 generating I steam, for the reason that {one ffire will answer for heating both-the air and the boiler but, if desirable, aseparate air-heatingappa ratus may be employed. Theair is supplied a forcing-pump, Y S, of suitable construction, which may 1 be. i worked by means of the engine, so that the supply of air will be commensurate to, the de mand. The safety-valves and governor-valv may be arranged inany manner found most convenient. The goyernor-valve amay be ap 1 plied to the pipe Di leading from the valve, chest to the air andsteam-pipjes; i i It will be seen fromthe above descriptiom that I bring highly-heated airland common steam together in thevalve-chest, and atsuit able times allow this mixtureto enter the cyl inder of the engine andact uponthe piston The air should be of a greater degree of tem perature than the steam, and its pressure may, be equal or greater than thesteam used, so that as soon as the two are mixed in the valve chest the temperature of the steam will b suddenly augmented, which will not only in crease its eitectiveness upon the piston, bu will prevent it from condensing while acting thereupon. By heating the considerablyly and using common steam, the latter may be superheated and its elasticity increased to an almost unlimited degree after leaving the boiler, and while communication between the boiler and valve-chest is cut oft. The introduction. of steam and heated. air into the valvechest is effected by means of the valves above described, controlled by the fly-wheel shaft of the engine, so that when steam is let into the valve-chest and the steam-valve closed, the air valve will be opened, and compressed heated air let into the val ve-chest, which will instantly reheat the confined steam more or less, according to the temperature of the air.

I am aware that it has been suggested to employ air mixed with steam as a force for driving engines, such air being forced into a chamber at a cool temperature, and thus mixed with steam therein. In this case itis ob vious that the air will instantly abstract from 'the steam a certain amount of its heat, and

hence destroy its efficiency. I am also aware that it has been suggested to mix cool air and steam together in a chamber and raise them to a high temperature before conductingthe mixture to the engine. I do not therefore claim broadly as my invention the use of air and steam mixed, as a force for driving engines; nor do I confine my invention to the particular form of engine herein described.

I have shown its application to this Well-known form of engine, as one practical mode of carrying it into effect, as one mode of reheating or super-heating steam on its way to the en,- gine-eylinder by the application of highlyheated air without raising the temperature of the steam in the boiler or increasing the pressure therein.

\Vhat I claim asnew, and desire to secure by Letters Patent, is

1. Reheat-ing or superheating steam, after it has left the generator, by means of highlyheated air introduced into the steam-chest under considerable pressure, substantially as described.

2. I claim applying steam and air within. the valve-chests or cylinders of engines, by introducing air into said cylinders when the air is heated to a temperature equal to or greater than that of the steam, substantially as and for the purpose described.

Thesteam-pipe D and hot-air pipe D, communicating with the valve-chest of an engine, and provided with suitable valves for alternately shutting oil and letting on the steam and air, substantially as described.

JOHN BLAKE TARR.

Witnesses:

EDW. SCHAFER, EDM. F. BROWN. 

